Unsaturated aldehydes and in the manufacture thereof



Patented May 22, 1928.

UNITED. STATES 1,670,825 PATENT OFFICE.-

HANS RUPE, OF BASEL, SWITZERLAND, ASSIGNOR TO SOCIETY OF CHEMICAL INDUS- TRY IN BASLE, 0F BASEL, SWITZERLAND. I

UNSATURATED ALDEHYDES AND IN THE MANUFACTURE THEREOF.

No Drawing. Application flied Marcli 11, 1927, Serial No. 174,702, and in Switzerland March 22, 1926.

This invention relates to unsaturated aldehydes and it comprises the process for the manufacture thereof, as well as the new products themselves.

It has been found that unsaturated aldehydcs of considerable technical value, espe- Analogous aldehydes may be obtained from other cyclic or aliphatic or aromaticaliphatic acetylene alcohols with terminal acetyl groups. Thus, for instance, from etliinyl-methylphcnylcarbinol there' may be produced ,B-methylcinnamic aldehyde; from ethinyl -dimethylcarbinol the isopropylidene-acetaldehyde; from ethinyl-ethylmethylcarbinol the sec. butylideneacetaldehyde, from ethinyl-methyl-isobutyl-carbinol the methyl-is0amyliden-acetaldehyde, and so on.

The acetylene alcohols which serve as parent materials can be made by the known processes from ketones and acetylenes (compare, for instance, Liebigs Annalen 308 (1899), page 2641), particularly by the action of an acetylene on the sodium compound of a ketone (compare Comptes Rendus 17 1, (1922) 1427; Bull. Soc. Chim. (4) 35, 597, 604). I

The new compounds possess a very characteristic strongsmell and are thus applicable for the manufacture of perfumes. They are further characterized by a very remarkable degree of reactivity and may thus serve as intermediates for the prepare tion of all kinds of synthetic products, f. i. synthetic drugs.

The following example illustrates the,invent1on:

1 part b weight of l-ethinylcyclohexanol- (1) ull. Soc. Chim. 35, 597) is cautiously warmed with 4-5 parts by vol- 'ume of formic acid of 85 per cent strength in a reflux apparatus until reaction begins. The heating is then interrupted, the mixture begins spontaneously to boil vigorously, the temperature at first rising to the boiling point of formic acid, but afterwards falling before the conclusion of the reaction. \Vhen the spontaneous reaction is at an end, the mixture is boiled, then cooled and poured into water. The formic acid is cautiously neutralized by means of sodium carbonate and the desired aldehyde is either extracted by means of ether or distilled with steam. It is purified by distillation under diminished pressure. If it is desired to purify the aldehyde still further, this may be done in known manner by means of the bisulphite compound or the semicarbazone or the oxime. I

The cyclohexylidene-acetaldehyde thus obtained is an oil having an odour which is a mixture of those of peppermint, benzaldehyde and mesityloxide; it boils at 78-80 C.v under 10-11 mm. pressure and yields a semicarbazone of melting point 200205? C.

In similar manner there may be obtained from l-ethinyl 3 methylcyclohexanol (1) (boiling point 7678 C. under 10 mm. pressure; melting point 77.5 C.) the 3-methy1- cyclohexylidene-acetaldehyde which boils at 8385 C. under 10 mm. pressure and has an odour similar to that of the aldehyde described in the above example. Its semicarbazone melts at 203 C.

1 ethinyl-Q-methyl-5-isopropyl-cyclohexanol- (1) (boiling point 108109 C. under 11 mm. pressure) yields the 2-methyl-5-isopro-pyl-cyclohexylidene-acetaldehyde which boils at 115 C. under 9.5 mm. pressure and forms a semicarbazone of melting point 140.5 C.

Ethinyl-dimethyl-carbinol (compare Inebigs Annalen 442, page 79) yields the ISO- propylidene-acetaldehyde o emf whose semicarbazone melts at 244 C'.

From ethinyl-inethyl-ethyl-carbinol (compare Licbigs Annalen 442, page 80) there is obtained the sec. butylidcne-acetaldehyde which boils at leis-i 31 C. and forms a semicarbazone of melting point 170 (l.

Eth-inyl-methyHsolmtyl-carbinol (boiling point -156 C. at atmospheric pressure) yields the methylisoarnylidene-acetaldehyde (llln 7 Gun U boiling 85-8t5 L). under 9 1mm. pressure and yielding a semicarbazone of the melting point C.

What I claim is 1. A process for the manufacture of unsaturated aldehydes by treating acetylene alcohols which contain a free hydrogen atom in the acetylene group, with a soluble body containing an acid radical.

2. A process for the manufacture of unsaturated aldehydes containing the group by treating acetylene alcohols containing the group on wherein the free valences are each saturated by a hydrocarbon radical, with a body containing an acid radical.

3. As new products the herein described unsaturated aldehydcs which possess at least one double bond situated between the two carbon atoms being in the a and ,8 po-- sition to the aldehyde group and which con stitute bodies of a characteristic odour and are useful as perfumes or as intermediate products for the preparation of pharmaceutical and other synthetic products.

4. As new products the herein described unsaturated aldehydes which contain the group wherein the free valences are each saturated by a hydrocarbon radical, and which constitute bodies of a characteristic odour and are useful as perfumes or as intermediate prodacts for the preparation of pharmaceutical and other synthetic products.

In witness whereof I have hereunto signed my name this 1st day of March, 1927.

HANS RUPE. 

